Ribbon lift mechanism



Sept. 13, 1966 P. F. PAGE RIBBON LIFT MECHANISM 2 Sheets-Sheet 1Original Filed Sept. 12, 1962 mw mw O R R @w .1! WM i 1. i @w m fiw mwon mm m K vw SQ Q3 it Qkm INVENTOR PAUL E PAGE Fem Wm ATTORNEYS Sept.13, 1966 P. F. PAGE 3,272,305

RIBBON LIFT MECHANISM Original Filed Sept. 12, 1962 2 Sheets-Sheet 2 Fig-iA INVENTOR PA E PAGE I 2044/ ATTORNEYS United States Patent Ofiice3,272,305 Patented Sept. 13, 1966 This is a division of applicationSerial No. 223,159, filed September 12, 1962.

This invention relates to ribbon lift mechanism for typewriter machinesand more particularly to a ribbon lift mechanism for lifting a ribbonvertically from a rest position upwardly into the print line.

Mechanisms of the general type here under consideration have been incommercial use for some time and usually operate more or lesssatisfactorily but uneconomically since they require intricate leverswhich present many manufacturing problems. Such a mechanism which isdifficult to manufacture, for example, is a parallelogram type of liftmechanism wherein a pair of lift arms are welded to a rod to make up thesides of a parallelogram frame for lifting a ribbon. Other machines usesimple lift mechanisms consisting of levers and cams which however donot provide a substantially vertical ribbon motion but a verticallyarcuate type of motion and which result in character smudges and perhapseven interference between the ribbon and the paper.

In accordance with one embodiment of the invention, the free end of avibrator arm which is pivotally mounted for arcuate motion is linked toa follower pivotally secured to the ribbon support. The fol-lower isadapted to ride in an arcuate slot formed in a guide aflixed to theframe. Since the arcuate slot is not concentric with the arcuate motionof the arm, the path of motion of the ribbon support is linearlyvertical.

It is accordingly among the objects of the present invention to providea ribbon lift mechanism for actuating a ribbon in a substantiallyvertical plane.

Another object of the present invention is to provide a ribbon liftmechanism which is easily manufactured.

A further object of the invention is the provision for preventinginterference between the ribbon and the paper by insuring the path ofmotion of the ribbon in a substantially vertical plane.

Still another object of this invention is to provide an improved ribbonlift mechanism.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings in which like referencenumerals designate like parts throughout the figures thereof andwherein:

FIGURE 1 is an isometric view of the vibrator mechamsm;

FIGURE 1A is an elevation of a vibrator arm;

FIGURE 1B is a fragmentary elevation showing the relation between thevibrator and printing head.

As shown in FIGURE 1 a portion 20 of the typewriter frame supports abracket 21 which carries a shaft 22 on which a ribbon vibrator assembly,generally indicated at 23, is rockably mounted. Vibrator 23 includes apair of arms 24 and 25 provided respectively with ribbon supports 130and 27 for a ribbon R which is adapted to be fed unidirectionally duringsuccessive typing operations in a manner described below. Arms 24 and 25are substantially similar to the right of shaft 22 and are joined by apin 26 which anchors one end of a return spring 26a, the other end ofwhich is fastened to frame 20, spring 26a biasing the arms downwardly totheir normal or rest position. Ribbon supports and 27 are respectivelycontrolled in their vertical reciprocatory movement by frame supportedguides 28 and 29 which have cam slots 28a and 29a adapted to receive camfollower pins 30 and 31 respectively. Pins 30 and 31 are secured to theends of crank levers 32 and 33 respectively which are integrally formedwith their respective ribbon supports 130 and 27 and are pivotallymounted to the ends of arms 24 and 25 by pins 24a and 25a. Thus, as thevibrator assembly 23 is rocked counterclockwise (as viewed in FIGURE 1),to elevate the ribbon supports, the ends of arms 24 and 25 follow anarcuate path which would cause the ribbon supports to follow an arcuatepath were it not for the shape of the cam slots 28a and 29a.

That is to say, that the path of motion of the ribbon supports isadjusted and changed by the cam follower pins 30 and 31 which engage thecam slots 28a and 29a to pivot the ribbon supports around theirrespective pins 24a and 25a. Thus, by shaping the arcuate cam slots 28aand 29a to be non-concentric with the arcuate paths of movement of arms24 and 25, the ribbon supports may be positioned in a vertical planeduring the rocking of arms 24 and 25, thereby to present ribbon R in avertical plane at the printing position. In other words, the arcuatemovement of arms 24 and 25 is converted into linear vertical movement ofsupports 130 and 27. Conventional carbon ribbon usually measures aboutfor reasons detailed below I prefer to use a carbon ribbon about /2"wide. Accordingly, the depth of the ribbon receiving slots 130a and 27ain supports 130 and 27 is slightly greater than /2", the supports beingprovided with ribbon retaining fingers 26b and 271) which help tomaintain the ribbon flat in a vertical plane as it is reciprocatedduring ope-ration of the vibrator.

An actuating arm, generally indicated at 34, is pivotally mounted on apin 35 carried by frame 20 and includes a crank 36 and a bifurcateddrive arm 37, crank 36 and arm 37 being secured together in any suitablemanner so as to oscillate as a unit about pin 35. As shown in FIGURE 1B,the lower end 36a of crank 36 is bifurcated to receive a pin 38 carriedby a lever 39 fastened to a drive shaft 40 adapted to be oscillated by asuitably driven bell crank'70 whereby actuating arm 34 is rocked forthand back about pin 35.

The two :sides 37a and 37 h (FIGURE 1) of drive arm 37 have identicalelongated slots 41 formed respectively therein through which extends apin 42 that also extends through a slot 43 formed in a bichrome lever 44whose lower end is pivotally connected to frame 20 in any suitablemanner. It may be seen that pin 42 may ride forth and back in slots 41and up and down in slot 43 for a purpose described below.

As shown in FIGURE 1A vibrator arm 25 includes a body 45 and a shoulder46 the latter having a slot 47 formed therein having a bottom edge 48and which is wider at its open end 47a than at its closed end 4712. Thisslot is adapted to receive pin 42 at any of the three positions, A, B,and C, to which it is selectively adjustable by manipulation of lever44. As will become apparent hereinafter, position A is a fabric ribbonposition operative to impart a full stroke to the vibrator arms so thattyping will occur on the lower field of a fabric ribbon. Position B is afabric ribbon position as well as a carbon ribbon position. With theapparatus conditioned for fabric ribbon and with lever 44 in the Bposition the vibrator arms can effect only a partial stroke so thattyping will occur on the upper field of a fabric ribbon; with theapparatus conditioned for carbon ribbon and with lever 44 in the Bposition the vibrator arms will effect partial 'parts are in theirnormal position the bottom edges of slots 41 are in registry with bottomedge 48 (FIGURE 1A) of slot 47, pin 42 resting thereon in its Bposition. 'If now lever 39 is driven counterclockwise (FIGURE 1)actuating arm 34 will be rocked clockwise thus forcing pin 42 againstslot edge 48 on vibrator arm 25 causing this arm as well as arm 24 torock counterclockwise and partially elevate ribbon supports 27 and 130.Thus with 'the apparatus conditioned for fabric ribbon, the position oflever 44 determines the length of the moment arm (distance between pin42 and shaft 22) thereby specifying either a full or partial stroke. Onthe other hand, with the apparatus conditioned for carbon ribbon, thelever 44 remains in the B position and the moment arm is changed in amanner to be described below.

According to the embodiment of the invention illustrated, the mechanismfor alternately elevating the vibrator arms to a partial stroke and thento a full stroke is the same as the mechanism disclosed and claimed inmy copending patent application 223,159 filed September 12, 1962.Therefore, insofar as is thought necessary, certain parts and functionsof this mechanism will now be briefly described. Referring to FIGURE 1,I provide a cam and ratchet combination generally designated by numeral50. The cam 51 takes the form of a Maltese Cross with symmetrical camsurfaces separated by radially extending valleys and may be integrallymolded from a suitable plastic with a ratchet 54. The cam and ratchetcombination 50 is mounted on a pin 59 such that when arms 24 and 25 arerocked up and down cam and ratchet 50 move with body 45; rotation of thecam and ratchet being effected as a result of return to rest movement ofthe arm as will be described below. A pawl 60 is pivotally mounted on apin 61 secured to frame 20 and is biased counterclockwise by a spring 62so that its tooth 60a tracks along the path defined by the teeth onratchet wheel 54.

Another pawl 63 is pivotally mounted on a pin 64 secured to vibrator armbody 45 and is biased counterclockwise by a spring 65 so that it tracksover the same path as that of pawl tooth 60a. Cam and ratchetcombination 50 together with pawl 60 coact with a drive pin 68 mountedon drive arm 37 to effect alternate full and half stroke drives ofvibrator arms 24 and 25 in a manner now to be described.

Thus, during the first half cycle of operation (driving stroke) theribbon supports 27 and 130 are driven a full or partial stroke dependingon Whether a cam surface or a cam valley is positioned under drive pin68 at the start of the cycle. During the second half of the cycle(return to rest stroke), cam 51 is indexed by pawl 60 and 'ratchet 54 toposition the next cam surface or valley, as

the case may be, beneath pin 68 in preparation for the start of the nextcycle. In other words, the moment arms are alternately 42-22 and 68-22depending on the location of cam 51.

It is now apparent that the conditioning necessary for using fabricribbon with the lever 44 in the B position a simply requires thedisengaging of pawl 60 from ratchet 54 and insuring that a cam valley isunder pin 68. As shown and described in my aforementioned copendingapplication 223,159, a lever, such as the lever 145, may cooperate witha pawl lug 60b and engage one of the studs 160 to provide both of thesefunctions.

As shown in FIGURE 1B, shaft 40 is mounted on a part of frame 20. Asnoted above bell crank 70 is secured to shaft 40 and has an arm a thatis connected to the drive mechanism (not shown) of the machine. Theother arm 70b of bell crank 70 is drivingly connected in any suitablemanner to a shaft 72 reciprocally mounted in frame 20, the upper end ofthis shaft carrying a matrix or spring head 73. Vibrator arms 24 and 25(FIGURE 1) straddle head 73 (FIGURE 1B) as also do ribbon sup ports and27 which accordingly support the ribbon near the printing head at theprinting position during a printing operation. Thus when crank 70 isdriven head 73 and ribbon supports 130 and 27 are elevated so that atype character on head 73 and the ribbon are presented at the printingposition where a hammer 74, driven by any suitable mechanism (not shown)effects an imprint in the well known manner.

It may now be seen that 'I have provided a ribbon handling mechanismthat attains the several objects set forth above in a thoroughlypractical and eflicient manner.

As other embodiments of the invention are possible and as changes may bemade in the one disclosed without departing from the scope of theinvention it is to be understood that the foregoing should beinterpreted as illustrative and not in a limiting sense.

I claim:

1. In a mechanism for moving a typewriter ribbon vertically with respectto a point of contact between a print element and a hammer or platen,the combination of,

a frame,

a pair of outwardly extending vibrator arms pivotally mounted on saidframe the ends of said arms describing an arcuate path during pivotalmovement thereof,

drive means for rocking said arms in synchronism with each typingstroke,

ribbon support means pivotally mounted on said arms for maintaining theribbon in a vertical plane,

cam means secured to said frame,

and cam follower means secured to said ribbon support means and adaptedto engage said cam means thereby to pivot said ribbon support means onsaid arms such that said ribbon support means are maintained in avertical plane when said arms are rocked.

2. A mechanism in accordance with claim 1 wherein said cam means iscomprised of a pair of cam plates each having an arcuate slot which isnot concentric with said arcuate path and said cam follower means iscomprised of a pair of depending arms each having a cam follower adaptedto ride in a different one of said slots.

References Cited by the Examiner UNITED STATES PATENTS 493,255 3/1893Densmore 197-167 581,500 4/1897 Webb 197-167 662,147 11/1900 Gabrielson197-158 949,257 2/1910 Barney 197-158 1,064,703 6/1913 Brown 197-1571,211,203 1/1917 McLaughlin 197-157 X 2,161,856 6/1939 Coxhead 197-1512,692,556 10/1954 Anderson 197-157 X 2,747,718 5/1956 May 197-1572,840,218 6/1958 Pelton 197-158 X 2,919,008 12/1959 Whippo 197-157FCREIGN PATENTS 16,563 1913 Great Britain. 381,472 10/ 1932 GreatBritain.

ROBERT E. PULFREY, Primary Examiner.

E. T. WRIGHT, Assistant Examiner.

1. IN A MECHANISM FOR MOVING A TYPEWRITER RIBBON VERTICALLY WITH RESPECTTO A POINT OF CONTACT BETWEEN A PRINT ELEMENT WITH A HAMMER OR PLATEN,THE COMBINATION OF, A FRAME, A PAIR OF OUTWARDLY EXTENDING VIBRATOR ARMSPIVOTALLY MOUNTED ON SAID FRAME THE ENDS OF SAID ARMS DESCRIBING ANARCUATE PATH DURING PIVOTAL MOVEMENT THEREOF, DRIVE MEANS FOR ROCKINGSAID ARMS IN SYNCHRONISM WITH EACH TYPING STROKE, RIBBON SUPPORT MEANSPIVOTALLY MOUNTED ON SAID ARMS FOR MAINTAINING THE RIBBON IN A VERTICALPLANE,